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Causes and solutions of ovality defects of aluminum profiles

Generally, the upper and lower deviation values of single finger round (shaped) aluminum alloy pipes. The reason for the out of tolerance of validity of round (shaped) pipe is mainly in the manufacturing of aluminum extrusion die, which has little to do with the design of aluminum extrusion die.
Causes:
(1) During manual milling, digging, planing and cutting of aluminum extrusion dies, the size, shape and processing of feed cavity, welding chamber and die core are asymmetric and the finish is inconsistent. This is the main reason. Many die factories introduce machining centers at any cost, and computer-controlled automatic machining programs are a great guarantee for the dimensional accuracy of symmetrical dies (including circular tubes). Eliminate the factors of large size deviation and uneven flow rate caused by manual processing!
(2) The ratio of the wall thickness of the aluminum alloy round pipe to the length of the working belt is incorrect (about 1:2.5). The ratio of too large to too small increases the factors of flow rate and friction, affects the aluminum flow of the working belt of the aluminum extrusion die, increases uncertain factors, and causes speed.
(3) The strength of aluminum profile die, the strength of die core, the size of upper die empty knife and the smoothness of bridged wire hole can all be affected.
(4) The extrusion speed of aluminum profile is too fast or the traction force is too large, and the stretching amount is too large.
Elimination methods:
(1) Making qualified and high-quality aluminum extrusion die is the fundamental!
(2) In aluminum extrusion production, it is important to control the speed, otherwise the surface is easy to be rough, because the empty knife of round pipe is generally not very large (0.5mm), and Musing particles are easy to stick. In order to obtain the surface quality and make the working zone short, the discharge is smooth but not pressure resistant, it is generally necessary to nitrite 40-50 rods after nitrating in the new mold.
(3) When producing double hole and porous thin-walled aluminum alloy pipe, we should pay more attention to the influence of the traction force on the outer diameter of the profile and the validity of the aluminum profile. Due to the relationship between the speed of discharging, the traction force is often concentrated on the one with the slowest discharging.

Aluminum profile frame


Post time: May-20-2022